Less pain reported with 34-gauge vs. 33-gauge needle for facial anesthesia injection

Key takeaways:

• The average pain scores were 0.79 and 0.49 in the 33- and 34-gauge groups, respectively.
• Subgroups including women and first time Mohs patients saw the most reduction in pain when using 34- vs. 33-gauge needles.

Specific groups may experience less pain during anesthetic facial injections when a 34-gauge needle is used vs. a 33-gauge needle, according to a study.

“The pain associated with penetration of the needle into the skin and the infiltration of the local anesthetic agent is often the only pain experienced by patients during outpatient procedures,” Kourosh Beroukhim, MD, of Houston Methodist Hospital and DermSurgery Associates, both in Houston, and colleagues wrote.

“A prior study demonstrated that a significantly smaller proportion of patients experience pain with the injection of local anesthetic using a 33-gauge needle compared to a 30-gauge needle,” the researchers wrote. “However, even when using a 33-gauge needle, close to 25% of patients still felt some level of pain with injection of local anesthetic to the face.”

In the prospective, randomized, controlled, single-blinded study, 483 patients were randomly assigned to receive an anesthetic inserted at a 15-degree angle or less with a 33-gauge (n = 242) or 34-gauge (n = 241) needle. Using the validated numerical rating scale (VNRS)-11, patients reported their pain levels on a scale of 0 (no pain) to 10 (worst pain imaginable).

Results showed that patients injected with the 34-gauge vs. 33-gauge needle reported significantly less pain during their initial injection (0.49 vs. 0.79; P = .007). Two-thirds of patients injected with the 34-gauge needle rated their pain as a 0.

On the VNRS-11 scale, women (P = .029), first time Mohs patients (P = .022), patients aged younger than 65 years (P = .002), patients with basal cell carcinoma (P = .006) and those with tumor locations on the nose (P = .022) experienced statistically significantly less pain when the 34-gauge needle was used vs. the 33-gauge needle, respectively.

The authors concluded that while both groups reported very low levels of pain during injections, the 34-gauge needle may be reserved for the specific aforementioned groups.